Added MDNS and driver support for multicast

tutorials/stm32/nucleo-f746zg-make-baremetal-builtin-cmsis_driver/main.c

@@ -60,6 +60,7 @@ int main(void) {
 
   MG_INFO(("Initialising application..."));
   web_init(&mgr);
+  mg_mdns_listen(&mgr, "Mongoose");  // Start mDNS server
 
   MG_INFO(("Starting event loop"));
   for (;;) {

tutorials/stm32/nucleo-f746zg-make-baremetal-builtin-cmsis_driver/mongoose_config.h

@@ -9,3 +9,5 @@
 #define MG_ENABLE_PACKED_FS 1 
 #define MG_ENABLE_DRIVER_CMSIS 1
 #define MG_ENABLE_LINES 1
+#define MG_ENABLE_MDNS 1
+